Recurrent invasive pneumococcal disease in children: Epidemiological, microbiological, and clinical aspects from a Danish 33-year nationwide survey (1980–2013)

Abstract

Background: Pneumococcal diseases play a major role in human morbidity and mortality. We present the results of a Danish nationwide study of recurrent paediatric invasive pneumococcal disease (rIPD) focusing on the epidemiological, microbiological, and clinical aspects. Methods: All laboratory-confirmed cases of IPD in children aged 0–15 y were identified from the Neisseria and Streptococcus Reference Laboratory, Statens Serum Institut, Denmark for the period 1980–2013. rIPD was defined as isolation of Streptococcus pneumoniae from any normally sterile site ≥ 30 days after an initial positive culture. Clinical data were obtained for all children with rIPD. Results: Of all children with IPD, 2.4% (59/2418) experienced at least 1 episode of rIPD, and an underlying condition was documented in 39 (66%). Immune deficiency due to transplantation (n = 9) was the most common disease; however, anatomic abnormalities (n = 8), complement C2 deficiency (n = 4), and congenital asplenia (n = 3) were all registered more than once. No underlying disease was detected in 18 children (31%). Based on the serotype distribution of S. pneumoniae isolates in rIPD among children aged 0–5 y (n = 41), 51%, 66%, and 78% of the cases would have been covered by the 7-, 10-, and 13-valent pneumococcal conjugate vaccines, respectively. Conclusions: Of children with an IPD episode, 2.4% experienced rIPD, and an underlying disease was documented in 66% of these children. Investigation of underlying conditions is essential in episodes of rIPD.

Keywords::

• Immune deficiency
• pneumococcal vaccines
• recurrent disease
• Streptococcus pneumoniae
• underlying disease

Acknowledgements

We thank the Danish Departments of Clinical Microbiology for submitting invasive pneumococcal isolates for national surveillance and the committed staff at the Neisseria and Streptococcus Reference Laboratory of Statens Serum Institut. We also thank all the paediatric departments in Denmark for allowing access to their patient archives. A special thank you to paediatrician Hans Erik Nielsen, DMSc, Department of Paediatrics, Gentofte Hospital, for valuable discussions and ideas during the initiation of the study.

Declaration of interest: The authors have no conflicts of interest to declare.

This research was supported by a grant from Oda and Hans Svenningsen's Foundation and Lykfeldt's Legat.